103877-07-2Relevant articles and documents
REACTIONS OF (-)-PHYSOSTIGMINE AND (-)-N-METHYLPHYSOSTIGMINE IN REFLUXING BUTANOL AND AT HIGH TEMPERATURE: FACILE PREPARATION OF (-)-ESEROLINE
Yu, Qian-Sheng,Schoenenberger, Bernhard,Brossi, Arnold
, p. 1271 - 1275 (2007/10/02)
(-)-Physostigmine (1), when refluxed in 1-butanol in the presence of sodium butylate afforded (-)-eseroline (3) in high yield, isolated as fumarate salt.Butyl N-methylcarbamate (4) was obtained from the mother liquor. (-)-N-Methylphysostigmine (2), prepared from 3 and dimethylcarbamoyl chloride, underwent under these conditions, similar decomposition suggesting that formation of 3 from 1 and 2 is the result of a nucleophilic substitution.Subliming, or distilling 1, in high vacuum afforded (-)-eseroline (3) and methyl isocyanate trapped by 1-butanol as butyl N-methylcarbamate (4).Compound 2 distilled without decomposition.It is suggested that pyrolysis of 1, therefore, proceeds by fragmentation, forming N-methylisocyanate and (-)-eseroline (3) as reaction products.